Creatinine

CPT: 82565
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Test Includes

Creatinine, serum; eGFR calculation


Expected Turnaround Time

Within 1 day


Related Documents


Specimen Requirements


Specimen

Serum (preferred) or plasma


Volume

1 mL


Minimum Volume

0.7 mL (Note: This volume does not allow for repeat testing.)


Container

Red-top tube, gel-barrier tube, or green-top (lithium heparin) tube. Do not use oxalate, EDTA, or citrate plasma.


Collection

Separate serum or plasma from cells within 45 minutes of collection.


Storage Instructions

Maintain specimen at room temperature.1


Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3


Causes for Rejection

Hemolysis; improper labeling


Test Details


Use

A renal function test used in eGFR calculation.2

High creatinine: Renal diseases and insufficiency with decreased glomerular filtration, urinary tract obstruction, reduced renal blood flow including congestive heart failure, shock, and dehydration; rhabdomyolysis can cause elevated serum creatinine. Low creatinine: Small stature, debilitation, decreased muscle mass; some complex cases of severe hepatic disease can cause low serum creatinine levels. In advanced liver disease, low creatinine may result from decreased hepatic production of creatinine and inadequate dietary protein as well as reduced muscle mass.3


Limitations

With reduced renal blood flow, creatinine rises less quickly than urea nitrogen. Concentration of creatinine only becomes abnormal when about half or more of the nephrons have stopped functioning in chronic progressive renal disease. Antibiotics containing cephalosporin lead to significant false-positive values if samples are drawn within four hours of a dose.4 With severe renal disease, creatinine is not reliable in the presence of cefoxitin therapy. There is less interference reported from the cephalosporins cephalothin, cephaloridine, cephadrine sodium, and cephaloglycin dihydrate. Lipemia, hemolysis, and bilirubin may interfere.5,6

Interfering Endogenous Substances7

Deviations

Degree of Interference

Pyruvate (serum/plasma)

>2.6 mg/dL

+12.8%

Glucose (serum/plasma)

>450 mg/dL

+16%

Ascorbic acid (serum/plasma)

>88 mg/dL

-10.1%

Urea (urine)

>12612 mg/dL

-11.0%


Methodology

Kinetic Jaffe


Reference Interval

See table.

Age

Female* (mg/dL)

Male (mg/dL)

*LabCorp internal studies.

Age/sex regardless

0.57−1.00

0.76−1.27

<2 m

0.44−1.19

0.44−1.19

2 to 11 m

0.17−1.18

0.17−1.18

1 to <3 y

0.19−0.42

0.19−0.42

3 to <5 y

0.26−0.51

0.26−0.51

5 to <7 y

0.30−0.59

0.30−0.59

7 to <9 y

0.37−0.62

0.37−0.62

9 to <11 y

0.39−0.70

0.39−0.70

11 to <13 y

0.42−0.75

0.42−0.75

13 to <15 y

0.49−0.90

0.49−0.90

≥15 y

0.57−1.00

0.76−1.27


Footnotes

1. LabCorp internal studies.
2. Levey AS, Stevens LA, Schmid CH; CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration). A new equation to estimate glomerular filtration rate. Ann Intern Med. 2009 May 5; 150(9):604-612.19414839
3. Takabatake T, Ohta H, Ishida Y, Hara H, Ushiogi Y, Hattori N. Low serum creatinine levels in severe hepatic disease. Arch Intern Med. 1988 Jun; 148(6):1313-1315.3377614
4. Durham SR, Bignell AH, Wise R. Interference of cefoxitin in the creatinine estimation and its clinical relevance. J Clin Pathol. 1979 Nov; 32(11):1148-1151.512029
5. Bowers LD, Wong ET. Kinetic serum creatinine assays. II: A critical evaluation and review. Clin Chem. 1980 Apr; 26(5):555-561.7020989
6. Soldin SJ, Henderson L, Hill JG. The effect of bilirubin and ketones on reaction rate methods for the measurement of creatinine. Clin Biochem. 1978 Jun; 11(3):82-86.688598
7. Roche Reagent Bulletin. TP-00523 Creatinine Jaffe Assays-Updated Endogenous Interference Claims. Dec 26, 2018.

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
001370 Creatinine 2160-0 001370 Creatinine mg/dL 2160-0
001370 Creatinine 2160-0 100779 eGFR mL/min/1.73 98979-8

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